<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .center {
            margin: auto;
            /*height: 100%;*/
            line-height: 300px;
            width: 100%;
            text-align: center;
            /*border: 3px solid green;*/
            padding: 10px;
            font-size: 50px;
        }
    </style>
</head>
<body>
    <div class="center">登录成功</div>
</body>
</html>